// 
// Copyright (c) 2006-2010 Ben Motmans
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//
// Author(s):
//    Ben Motmans <ben.motmans@gmail.com>
//

using System;
using System.IO;
using System.Security.Cryptography;

namespace Anculus.Core
{
	public class AutoStream
	{
		protected Stream inputStream;
		protected Stream outputStream;
		
		protected string fileName;
		
		protected bool createStreamFromFilename;
		protected bool disposed;

		public AutoStream (string fileName)
		{
			this.fileName = fileName;
			this.createStreamFromFilename = true;
		}
		
		public AutoStream (Stream stream)
		{
			this.inputStream = stream;
			this.outputStream = stream;
			
			this.createStreamFromFilename = false;
		}
		
		public AutoStream (Stream inputStream, Stream outputStream)
		{
			this.inputStream = inputStream;
			this.outputStream = outputStream;
			
			this.createStreamFromFilename = false;
		}
		
		public bool BaseStreamExists ()
		{
			return !createStreamFromFilename || File.Exists (fileName);
		}
		
		public Stream GetInputStream ()
		{
			return GetInputStream (null);
		}
		
		public Stream GetInputStream (AesKey key)
		{
			Stream stream = null;
			if (createStreamFromFilename)
				stream = new FileStream (fileName, FileMode.Open, FileAccess.Read);
			else
				stream = inputStream;
			
			if (key == null)
				return stream;
			
			return new CryptoStream (stream, key.CreateDecryptor (), CryptoStreamMode.Read);
		}
		
		public Stream GetOutputStream ()
		{
			return GetOutputStream (null);
		}
		
		public Stream GetOutputStream (AesKey key)
		{
			Stream stream = null;
			if (createStreamFromFilename)
				stream = new FileStream (fileName, FileMode.Create, FileAccess.Write);
			else
				stream = outputStream;
			
			if (key == null)
				return stream;
			
			return new CryptoStream (stream, key.CreateDecryptor (), CryptoStreamMode.Write);
		}
		
		public static implicit operator AutoStream (string fileName) 
		{
			return new AutoStream (fileName);
		}
		
		public static implicit operator AutoStream (Stream stream) 
		{
			return new AutoStream (stream);
		}
	}
}
